Male or female? What colors should I look for in a mate?

[Betsnest]

3 views of the same bird. Do I have a male or female? What colors should I look for in a mate? I don’t know anything about bloodline or crosses. Thanks

[Craig52]

You have a double factor Euro yellow cock bird.
You can mate him to a Euro yellow hen bird or a normal green back hen.
The mutation is sexlinked recessive dominant and you get Euro yellows and normal green back in the young as you can't get split Euro yellows to a normal green back hen.
Mated to a Euro yellow hen all young will be Euro yellows.
When adding white breast it's best to put white breast to white breast in green back or Euro yellow hens.

[Betsnest]

Thank you so much for your thoughtful reply! I just have one question- I’ve heard you shouldn’t breed white breast to white breast. Is there an exception in my case?

[Craig52]

Breeding white breast to white breasted is fine because it is a strong autosomal recessive mutation. The problem is you get splits if you breed a pure purple breasted bird to a white breasted bird that look normal and you sell those young on to someone that only likes purple breasted birds with the hidden gene for white breast. It becomes a little messy.

[Betsnest]

Thank you for your help. I understand what you are saying.